The present invention relates to a method of using tickets on smart cards, and to smart cards in which tickets are stored. In particular, the present invention relates to the secure storing, validating and verifying of multiple tickets on smart cards, multiple tickets being tickets which may be used more than once. Such multiple tickets may e.g. be bus or train tickets which may be used for more than one trip, or theatre tickets which can be used for more than one performance or more than one person.
There is a growing need for storing tickets on smart cards as the use of smart cards and the number of applications for which they are used increases. Present day smart cards, however, have a limited memory size. The storing of a plurality of tickets on a single card is therefore only feasible if an efficient way of storing those tickets is employed. Especially multiple tickets, which give the cardholder multiple access to e.g. a service, take up a relatively large amount of memory space. Several schemes of using tickets have been proposed in the Prior Art, but none of these appears to provide an efficient way of storing multiple tickets.
Dutch patent application NL 93 01902 discloses a method of obtaining a right to a service by means of a smart card (IC card). In this Prior Art method, the card serves both as a payment means and as a registration means. That is, the card is used to store proof of payment of the service paid for, thus replacing paper tickets. The use of multiple tickets, i.e. tickets which may be used more than once, is also mentioned in said patent application.
In the method of the above-mentioned patent application, a ticket is stored on a card by registering on the card an access code, optionally in combination with a card identification code. At the terminal of e.g. a theatre the access code and (optionally) the identification code are checked, whereupon the access code is erased from the card. The way multiple tickets are implemented is not disclosed. The above-mentioned patent application therefore does not provide a specific method for securely storing tickets on smart cards, and certainly not for multiple tickets.
European Patent Application EP 0 658 862 discloses a method and system for employing multi-functional smart cards by means of a communication system. This prior art method and system allow e.g. airline tickets to be stored on the smart cards. The specific manner in which the tickets are stored is however not disclosed.
U.S. patent application Ser. No. 08/908,716, filed on Aug. 8, 1997 assigned to the present assignee, and entitled "Tickets stored in smart cards" describes the use of tickets on smart cards, in particular the use of validation and verification fields to issue, validate and verify tickets at different locations and at different points in time respectively. The above-mentioned U.S. patent application, which is incorporated by reference herein, does not describe the use of multiple tickets.
The Prior Art therefore does not provide an efficient way of storing multiple tickets in smart cards.